Adaptation for Survival 1
ADAPTATION IN ANIMALS
- If animals were not adapted to survive in the areas they live in, they would die
Key words:- adaptation, conserve, surface area, volume ratio, camouflage
- Many students do not understand surface area to volume ratio. It is a very important idea in science, The larger the animal, the smaller its surface area is compared to its volume
- Adaptations are not just to do with what an animal looks like; some adaptations are about the animals behaviour
Adaptation for Survival 2
ADAPTATION IN PLANTS
- Plants must be adapted to live in a variaty of climates, including deserts
- Plants must be adapted to survive being eaten by animals
Key words:- conserve, warning
- There are many ways plants conserve water in dry environments. These include extensive roots, waxy leaves, small leaves and water storage in stems. Don't limit yourself to one idea in an exam!
Adaptation for Survival 3
COMPETITION IN ANIMALS
Key points :-
- Animals compete with each other in many different ways
- The most successful ones survive and pass on their genes to the next generation
Key words:- predator, prey, camouflage
- There are many ways animals are adapted. Colour (to attract females or as camouflage) and speed (to catch food or escape from predators) are only two of them
Adaptation for Survival 4
COMPETITION IN PLANTS
Key points :-
- Plants compete for a number of resources
- Successful plants have structures and habits that allow healthy growth
Key words:- nutrients, habits
- Plants do have structures which enable them to compete, e,g, extensive root systems. However, in an exam question, it is also very important to mention that they may have successful growing habits, e.g. they grow quickly to gain as much light as possible, or they grow at a time when other plants are dormant e.g, snowdrops in a wood
- Information from parents is passed to the offspring in the genes
Key words:- nucleus, chromosome, gene, gamete
- It is the individual genes that control the characteristics of the offspring. Chromosomes are simply made up of genes
TYPES OF REPRODUCTION
Key points :-
- There are two types of reproduction - sexual and asexual
- There are very important differences between sexual and asexual reproduction
Key words:- sexual, asexual, clone, variation
Examiners tips :-
- Many students forget why one type of reproduction results in variation and the other doesn't. It is simply that in sexual reproduction genes are mixed from the two parents, whereas in asexual reproduction there is only one parent, so mixing is impossible
- Individuals identical to their parents are known as clones
- It is much more difficult to clone animals than it is to clone plants
Key words:- clone, cutting, tissue culture, embryo transplant, host
- In order to get top grades make sure you know why clones are identical to their parents and how the different types of cloning work. If you only know the names of the different types of cloning then this is only C/D grade knowledge
NEW WAYS OF CLONING ANIMALS
Key points :-
- Scientists can clone animals using fusion cell cloning and adult cell cloning
- There are benefits and risks associated with animal cloning
Key words:- fusion cell cloning, adult cell cloning
- There are arguments for and against cloning animals. Some people have very strong views. Make sure, in the exam, that you are able to put forward arguments for and against to get full marks
- Genetic engineering is used to ensure that organsims have desired characteristics
- New or alternative genes are added to the chromosomes
- Genetic engineering is the subject of much debate
Key words:- enzyme, gene, desired
Examiners tips :-
- It is the gene that controls how an organism develops. If you place a gene in a new organism it will develop that characteristic
THE ORIGINS OF LIFE ON EARTH
- We are unsure of when life began on Earth. No-one was about.
- However, fossils help us to decide when life began, although it is proving very difficult to find any really good evidence
Key words:- fossils, evidence
- Remember in an exam question to link fossils with rocks. They are found in different layers. This means we can put an approximate date on when different animals and plants existed.
THEORIES OF EVOLUTION
- There are two main theories of evolution. They are those of Lemarck and Darwin.
- Much evidence now points to the theory of Darwin being the correct one.
Key words :- acquired, natural selection
- In exams many students forget that the number of a species that survive go on to breed.
- This means their genes are passed on. Make sure you don't forget to write this and, therefore, miss out on a couple of marks
- Organisms of a species all vary from one another
- Some organisms are likely to survive and breed as they have better characteristics. This is known as natural selection.
Key words:- characteristics, fittest
- Remember that organsisms are adapted in many different ways. Survival of the fittest does not mean just the fastest. It might mean those able to find food best, fight off disease, survive a cold snap in the weather etc
- Many species have evolved and then become extinct in the life of the Earth
- Extinction means that all of the species has been wiped out
- There are a number of changes that can cause a species to become extinct
Key words:- change, disease, predator, competitor, climate change
- Make sure when answering a question about extinction that you always remember to use the word change. If there is no change, then species do not become extinct.
How people affect the planet 1
THE EFFECTS OF THE POPULATION EXPLOSION
- The human population is increasing rapidly. So we use up more resources and produce more waste and pollution.
Key words:- non-renewable, pollution, waste, indicators
How people affect the planet 2
- Sulphur dioxide is mostly responsible for acid rain
- Clouds blow across countries, so those producing acid rain often cause problems for somebody else!
Key words:- acid, dissolve, enzymes
- Remember that acidity does not dissolve the organism. Living things are killed as their enzymes only work in a narrow range of acidity / alkalinity (pH)
How people affect the planet 3
- It is now widely believed the the atmosphere on the planet is warming up due to our activities
- It is also agreed we should do something about it. Not everyone agrees what !
Key words:- combustion, carbon dioxide, methane, deforestation
- Remember methane is also a greenhouse gas. Many students in exam questions only mention carbon dioxide. However, never mention the ozone layer, it has nothing to do with it !
How people affect the planet 5
PLANNING FOR THE FUTURE
Key points :-
- Lichens are indicators of the level of pollution in the air. Freshwater invertebrates are indicators of pollution in fresh water
- In the development of new housing for increases in population it is important to use, as fully as possible, areas that have already been used for building and redevelop them. This helps in making development sustainable.
Key words:- lichen, freshwater inverterbrates, pollution, sustainable
- Make sure that you remember the two indicators of pollution. Lichens for air pollution and freshwater invertebrates for water pollution.